The present disclosure relates in general to the data exchange between various components of a technical system. In particular, the present disclosure relates to the cross-linking and configuration of various components of a technical system, in order to enable a data exchange among the components.
Technical systems, machines or devices increasingly comprise many electronic components, such as control units, sensors, and actuators. For an intended function of the device, often not only is communication of individual components with a central control unit necessary, but also communication of the components with one another. In principle, the components can be connected for this purpose to one another by means of proprietary communication lines, and thus cross-linked or interconnected with one another. This necessitates at least one line from the central control unit to each sensor and actuator (parallel wiring). With an increasing degree of automation of a system, machine, or device, the cabling effort and expense increase, given parallel wiring, because of the greater number of input/output points. This results in major effort and expense in terms of planning, installation, putting into operation, and maintenance.
It is known for the components to be cross-linked or interconnected to be connected serially by means of a so-called communication bus. To that end, all that is required is to make a connection, which is moved onward at each component (serial wiring). Thus the communication bus replaces the parallel bundle of lines with a single bus cable, which connects the individual components as a bus participant (bus node).
For this kind of serial cross-linking or interconnecting of the components, numerous network and bus technologies are known. One known example, which was originally developed for the motor vehicle field, is the Controller Area Network (CAN) bus. Physical facts about the CAN bus and other bus protocols, such as the Profibus are standardized internationally in ISO 11898, which defines Layer 1 (physical layer) and Layer 2 (data security layer) in the ISO/OSI reference model. CANopen is a further development; it is a Layer-7 communications protocol based on CAN. CANopen has been maintained since 1995 by CAN in Automation and has meanwhile been standardized as European standard EN 50325-4.
So that a communication or data exchange can function on the bus, the individual bus participant must be uniquely identifiable and thus also addressable. A further requirement of serial bus systems is that the bus must be terminated (bus termination) on the physical plane at each of its ends by means of termination resistors. All this requires careful planning and complicated and expensive implementation.
CAN bus systems known at present require a complicated configuration for each switch (such as a DIP switch) or so-called jumpers, by means of which each component connected to the bus is assigned a unique address or ID, and the requisite bus termination is activated at the component forming one of the bus ends.
The bus configuration must be defined when the system is assembled and can be changed or adapted, for instance if a further component is to be added, only at major effort and expense.
DE 10 2008 044 777 A1 discloses a method for addressing the participants of a bus system, having a control unit, a bus originating at the control unit, and a plurality of addressable participants, which are connected to the bus; the control unit feeds an identifying current to the participants; the identifying current is carried each via a respective electrical resistor that is assigned to a participant not yet addressed; each participant determines the voltage drop at the associated resistor; and for the sake of addressing, the participants are assigned an address, the voltage value of which address is distinguished from the voltage values of the other participants by a predeterminable threshold value, and the addressed participants short-circuit the associated resistor.
DE 10 2009 045 126 A1 discloses units, integrated in a communications assembly, of which each comprises one position recognizing unit, that decides on the basis of received and sent position-recognizing signals on a peripheral position or an internal position of the associated unit, and in the case of a peripheral position, it performs a termination.